1. Field of the Invention
The present invention is directed to the field of liquid level sensing and more particularly to the area of circuitry configured to sense the occurrence of low liquid levels and provide warning indications of such occurrences.
2. Description of the Prior Art
Many circuits have been utilized, in conjunction with liquid level sensors, to supply indication when liquid level is above or below a predetermined level. Some such level monitoring systems have been proposed for automotive use in order to measure the level of oil in the crankcase of an associated engine. U.S. Pat. No. 1,280,222; No. 3,605,086; and No. 3,939,470 describe circuits that continuously monitor the oil level during operation of the associated engine. A system has been proposed in U.S. Pat. No. 1,768,446 which incorporates manually actuated switches so that the operator may from time-to-time check to see if the oil level is below a critical level.